Trouble importing new pictures from an old folder

I'm using Lightroom 3 with a MacBook Pro. When I "edit in ... Photoshop Elements" I'll save the edited file as a JPEG in the same folder as the RAW file. But Lightroom won't see it for me to import it into the catalogue. When I look in a Finder window, I see the RAW file, the PSD file and the JPEG file. But in Lightroom, I only see the RAW and PSD files. Doesn't matter if I try to "copy", "add" or "move", the JPEG isn't visible. The only work around I've found is to save the JPEG somewhere else (desktop) and then to move it during import with Lightroom. What am I missing? Thanks.