First decide if you want to ride with him at all. If you don't just tell him so straight out. If you decide to ride with him... take the Lemond. Remember he's a newb and 15 or 20 miles to him might seem like a long way. Newbs and hills don't usually go together, so maybe take him up a few steep climbs just to "break him in right" but don't drop him just because you can. Try to have a good impact on his experience as a new Roadie. That may change his perception of how he comes across to other cyclsits. Do a casual ride and try to have fun. BUT!!..... if he acts like a "Tool" or starts trash talking, then you know what to do. And if you do have to put him in his place don't forget one of my favorite lines as someone mentioned above:

Then do like Cartman and blurt out, "Respect mah AUTHORI-TAH!"