Slightly more complicated than that.
When you click "Edit in CS6" (or whatever) you have the option of editing a fresh copy or editing a copy with Lightroom adjustments. Either way, Lightroom will create a Tiff file and shoot it over to CS6.
After you have finished editing in CS6, clicking "Save" in the CS6 File menu will result in the edited Tiff being imported by Lightoom with that image (in normal circumstances) appearing next to your original image in the Library module (or the Develop module filmstrip).
Where is can be a little confusing is if you edit in CS6 from a collection (such as "Last Import"). In that case the edited Tiff may not appear alongside the original in the collection - but you will find it if you select the original image and then click on "All Photographs" to display the entire catalogue.
At least, that's what I find. Same applies to images I edit in any of the Nik or Topaz programs after right-clicking in Lightroom.
My normal workflow is to do my basic post-exposure processing in LR5.3 and then, if I require/desire further processing in, say, CS6, SilverEfexPro, ColorEfexPro or whatever, I do that on a copy with my Lightroom adjustments. After saving the result back to Lightroom, I then apply any finishing touches in Lightroom before either exporting it as a Jpeg (if required for a competition, say) or printing. I always print from Lightroom, even if most of the processing has been in CS6.