I was startled to find that "C lisp"--that is, the lisp interpeter written in C, which you get when doing sudo aptitude install clisp on the latest Ubuntu distribution--is actually not the "standard" lisp interpreter. I still have no idea which is, if any.
Still, it seemed like a few of the web frameworks out there should have worked anyway, so I tried to soldier on for a while. Unfortunately, it was in vain: my dependency-fu simply wasn't strong enough. I also couldn't find a lisp equivalent to rack and wsgi, which is something of a non-starter imho.
I'm sure I am making some foolish assumptions, facilitated by the vast chasm that represents my experience with lisp and its ilk. I also have only managed to devote a few hours to it so far, so please, no one take this post as gospel--I'm just sharing what little I have found in case someone else finds it useful.