I may just be one of the uninformed, but I'm not aware of any named NPCs in Skyrim that respawn. Companions can't normally die (unless you accidentally or purposefully kill them when they're down on a timeout from damage), but if they do, they're dead. Period. AFAIK

OR:
Are you asking because you dismissed her or she wandered off and you're wondering where she'll return to so you can pick her up again? If so, all of them (so far that I've seen) have returned to their original place.