the big bang theory - Is Raj still working with Sheldon?

In season 4, episode 4, Raj moves a desk into the office against Sheldon's will.

In season 5, episode 7, we see the two of them working together in the office. Sheldon puts a snake in Raj's drawer.

In season 5, episode 17, Sheldon moves into his new office, and Raj says, "I’m happy for you, Sheldon. But I have to admit I’m going to miss sharing an office with you."

I cannot see where it has been addressed in season 6 as yet, but one would have to presume it will be if the situation changes.

You can find transcripts of the episodes here.