Have to ask the obvious question. Why not start in Lightroom for all your images?
Sometimes I just want to take one of my saved TIFF files and work in PS without loading it into LR...front end saves time, if I like what I've done in PS it's all good, but sometimes I like to use some of the LR tools after...does that make sense? Many times when using plug-ins I might do some heavy lifting, then the file comes back to LR and it's all fresh and new (heh...) and I can't resist messin' with some sliders...that kind've thing...sorry, I'm trying to explain a *very* personal workflow that isn't by any means strict...
Instead of going back to Lr why don't you just use an ACR filter in Photoshop.
...OK...well, it's kinda obvious that there isn't a way to do what I want...I *want* to do what I stated in the first post. Thanks for your replies, folks...I'm out...
Given your desire, the way I would do this would be to:
Edit as desired in Photoshop.
Save as PSD with full compatibility turned on.
Import the PSD file into LR.
Continue the editing in LR as needed.