Do you want "Close and Return to Lightroom" or "Save and Return to Lightroom"? What would this do different that simply choosing File>Save in Photoshop? Is it that you want Lightroom to become the front most application?
"Save and Return to Lightroom" would work quite well. I want LR to become the front most application for workflow reasons. When using Bridge, one can take an image into PS, process it, and return to Bridge without using the OS to switch applications. I use a PS action hooked to a Function key to flatten the image, save it, and return to Bridge. It's a simple "round trip." When LR is the front end, making the same round trip requires an action which flattens, "save as" (to get it to the originating folder), then use Windows alt-tab to return to LR.