OP, that is sort of what Lithium is supposed to do. I use the word "supposed" pretty liberally, because the desired effects are a more stable, functional person, but the reality is often just a slowing down and numbing of your emotions. It's a very commonly reported effect from Lithium. In short, because Lithium has this overarching numbing effect upon your emotions, you can expect the Lithium to subjectively alter the effects of the Clonazepam (Klonopin/Rivotril).
As far as describing all of this verbally, it's just a little bit too esoteric to put into words. You can expect the Lithium to alter the subjective experience of the Benzodiazepines, but we will never be able to give you this "answer" that you're looking for.