that works less than orange and florins.
your dun geon
or ange one
the middle syllables sound nothing alike, the consonants being split up and the accents being in different locations in the first two syllables of both.
As for orange being mono-syllabic, just because YOU say it does NOT mean that most people say it that way. I say "woman" incorrectly, much to the amusement of oen of my close friends. However, the fact that I have learned myself to say it the way I do does not have any root in the number of people near me, let alone in the world, who say it the way I do. In fact, I don't know ANYONE who says it the way I do.
In addition to Fuzzy's argument, which I find much more compelling than your own (-sexual is the FIRST thing I think of to rhyme with intellectual, actually, and that rather quickly).
But my most solid argument in this case is that if you can say that rhyming "orange" with "florins" violates the purpose of rhyming the final words entirely, then you are paying no attention whatsoever to what my couplet is saying. Because for the purposes of the couple, slant rhyme is exactly what is called for. A better rhyme (were there one) would weaken the meaning.