Seems to be a bug in Lightroom 2 when you edit in Photoshop. When you finish editing in Photoshop and save, the edited file is saved in the same folder as the original, but not automatically imported into Lightroom. You have to manually import it if you want it in your catalog. The workaround I found online is to set your preferences up so that Photoshop.exe is the second choice for external editing. If you edit in Photoshop.exe all works normally.