Yes, you can. You could also say high comedy or highbrow humor/comedy, smart humor,
If you're ever worried about collocations in a language you're learning, try googling the phrase with quotation marks e.g. "lofty humor." Your results will return with pages that use these two words in that order. Check how many times this has been used in the results; if it's been used more than a couple hundred thousand times, then I'm inclined to say that the phrase passes for common English parlance. In this case, we have 2,300 odd results for "lofty humor," and only 700 or so for "lofty humour," which isn't a good sign! But, and this is a big but, let's look at the sources and how they are used. One source is the New Yorker, a very highly respected and reputable magazine with a strong history of strict editorial no-nonsense. We can even see this phrased used in action: "Hitchcock's lofty humor," or the "lofty humour of Gogol," and since these appear in publications of note, we can safely assume these go together.