Trying to develop a new workflow. I have learned how to edit an image from LR4 in PS (CS5) but I don't know how to get it back to LR - I'd like it to replace the previous image in that work flow after I have touched it up in PS. Can someone walk me through that part? I want to publish from LR and keep that catalog. I don't want to catalog in PS. I just want to do touch ups.
You can use Save As but you need to do Import new from the file location in LR. Make sure you save as compatible file, which means Photoshop makes a stamp of all layers as an embedded TIFF along with the rest of all layers in the PSD file, so that LR can read it. If you constantly need to go back and forth between LR and PS, using Photoshop alone is a much better route in terms of reducing file size when you work with higher resolution camera files.
Using File > Save in Ps returns the edited file to Lr but it may not replace the original - in fact, it probably should not, especially if the original was a raw file. I think you would have to establish the rules within Lr preferences to govern where the externally-edited files will go, how they are stacked with the originals, etc.