They can handle pretty cool temps. I usually leave mine out until the nighttime temps drop below 45. I think it has to be at least 50 or below to get them blooming. Just do NOT leave them out if there is a chance of frost. Also, reduce water significantly. You don't want the pseudobulbs to shrivel up, but otherwise keep them pretty dry. Also reduce your fertilizer during the winter. They need a dry winter rest to kick in their bloom cycle.
I pm'd you about a website that has really specific cultural information for species too.