toki pona question: if i wanted to translate a sentence fragment, e.g. "in a dream", how would i do it? would this be "insa e sitelen lape", "li insa e sitelen lape", something else, or is it just straight up not allowed?

toki pona question: if i wanted to translate a sentence fragment, e.g. "in a dream", how would i do it? would this be "insa e sitelen lape", "li insa e sitelen lape", something else, or is it just straight up not allowed?
My mind went to "...lon (insa) lawa lape". "lon (insa) sitelen lape" makes sense too
"...(li) insa e sitelen lape" means "...causes a dream to be inside" (or something like that) though