Yes and no. Edits to RAW files will not show up in LR. Similarly edits to RAW files in LR will not show up in PL6. When you export from PL6 the edits are "baked in" to dng/tiff files. You can continue to edit in another program but the PL6 edits are permanent and therefore the starting point of additional external edits.
One thing I did learn from reading the manual is that you can edit what you did in PL6 starting in lightroom by clicking the original raw and resending it back to PL6. PL6 recognizes and applies it's own previous edits as a starting point for further tweaking and when you save back to Lightroom it gives you a choice to overwrite the existing dng or assign a unique name.