On the horizon
Some of the time -- not all, but some -- you'll see the lorestorm on the horizon. Expansions are announced, patches are planned for release, and you know that the gun on the mantle is going to go off. You might not have any control over when, but you do have control over the time up until then. Stop flying in a holding pattern and start pushing things toward a conclusion.
Cataclysm was a good example of this. Players knew well in advance that the expansion was going to seriously screw with the entire world, which meant that there was ample time to wrap up stories revolving around the existing landscape or political climate. If you wanted to finish a character's investigation of the Plaguelands and the plague's effects on wildlife, for instance, there was a great big chunk of time for that to be done. Heck, as it turned out, you hardly even needed to hurry.
Of course, that right there shows the negative of trying to complete arcs based on imminent lore changes. You might push hard, get a character arc wrapped up, and have the character ready for all the big changes... and find out that you still have two or three months until those changes go live. Cataclysm was also a spectacular example of this, with a test cycle that seemed to stretch on for ages. Needless to say, while it's always possible to do a little planning, counting on a timetable of "soon" is counterproductive. (Likewise, assuming that the big patches are far off isn't a good choice either, at least not if you're dabbling in areas you expect will be affected.)
And you won't always know in advance. Sometimes you'll be planning something with no knowledge that in the near future, what you thought was a blank spot for you to build something on is now the site of a major urban center. You'll have to develop more sophisticated coping mechanisms, something like...
Pretending something already happened
Your original plan was to have your Lore-master return to Bree, his town of origin, to retrieve a beloved childhood relic. It was going to be a simple and sweet little character arc, and it's been kind of derailed by the latest Lord of the Rings Online patch turning Bree into a PvMP war zone. (Note -- this has not actually happened, to the best of my knowledge.) Clearly, your best option here is to take a deep breath and pretend that what you were going to have happen did happen at some undisclosed point.
Sometimes the game -- or other roleplaying -- is going to wind up leapfrogging whatever you wanted to do. It can be something as big as a zone change, or it can be you expecting the game's story to explore a certain angle when the developers decide to more or less ignore it. Sometimes, the easiest way to make your character arc work is to just roll your eyes and fill in all of what would have happened as retroactive backstory.
This obviously only will work for smaller parts of your character arcs. Trying to make the aforementioned beloved childhood relic a piece of offhand backstory works. Trying to make a showdown in the streets of Bree, which would have included three declarations of love and two deaths, work as an offscreen event is at best ridiculous and at worst a worse kind of ridiculous. Which means there are other times when you've got to just get good at...
Rolling with left turns
So your character in Final Fantasy XIV is originally from Ishgard. And you have her talk about the city's spires, and the culture of the city, and airships and other parts that make logical sense from what is known about the city. And a few months from now, the gates to the city are flung wide open, which works out great for everyone other than you, because your character's statements about the city are now proven to be totally wrong. What do you do?
We're not going to bother talking about how it's best not to set up your character directly in the path of oncoming lore, because we all know that and we do it anyway. The stuff that's coming up is so tempting because it gives your character a sense of validity and an air of mystery all at once. How can you resist?
What you can do is accept that these turns are going to happen, especially if you pitch your tent in the aforementioned areas which are due for exploration. Look at the circumstances like a challenge. Clearly, your character's statements don't mesh with what actually happened -- why? Was she lying? Has the city changed since she was last there? Does she have a mental illness you didn't previously know about?
Obviously, this is going to require you to think on your feet and do some adaptive storytelling. But that's what roleplaying is all about -- the difference is that you're not interacting with another player -- you're interacting with the world. And while the world might not care about your character, that's something we're all intimately familiar with from the real world.
Next week, it's time to begin something not completely different but at least slightly so. Until then, mail comments to firstname.lastname@example.org or leave them in the comment field below.
Every Friday, Eliot Lefebvre fills a column up with excellent advice on investing money, writing award-winning novels, and being elected to public office. Then he removes all of that, and you're left with Storyboard, which focuses on roleplaying in MMOs. It won't help you get elected, but it will help you pretend you did.