Well, it used to be that Clojure targeted both .Net and the JVM. Now it just targets the JVM.
So... it can only run on .Net if it thinks it's talking to the JVM.
Does that make sense?
Scala was the same. Its now really JVM only - but IKVM does an amazing job in running things on .net if you need to (last I tried, which was quite a few years ago, the ikvm slowdown was single digit percentage, very impressive, over "native" .net code).
Lisp (Clojure) running on .NET (IKVM) sounds awesome. I wonder how practical it is.