Yep, you "degrumped" me, thank you for your fast and friendly response ! :)
In the meanwhile I checked lo out on internet and found this precious little gem:
Lo : for masculine singular nouns which start with:
s + consonant
lo studente, lo spagnolo, lo scontrino / the student, the Spanish guy, the receipt
lo zaino, lo zio / the backpack, the uncle
lo yogurt, lo yen / the yoghurt, the yen
lo psicologo / the psychologist
lo pneumatico / the tyre
lo gnomo / the gnome
I didn't find the double consonant rule, though.
In a certain context "It is anyway" would be correct; it'd be in response to someone saying e.g.: "The restaurant isn't open due to a fire." And someone responding, "It IS anyway," meaning it's open regardless of the fire. In this case, IS would be emphasized to show contrast. That said, I don't believe DL's sentence would be used that way.
My first (and only) real exposure to Italian, besides food/cooking terms, came from music. The marking "l'istesso tempo" (spelled that way, meaning "the music stays at the same speed) has long been familiar to me. Here I'm seeing "lo stesso" - can someone please explain the difference?
This is all new to me too, pjkaiser27, but could it be that ''lo stesso" is more of a pronoun while in your phrase "istesso" seems more like an adjective? (Just a guess!) Or maybe you have spotted an older Italian way of forming the definite article for words starting with s + consonant?
I googled around a bit and found this (https://musicterms.artopium.com/l/Lostesso.htm) "Lo stesso Definition and background: (or commonly, but ungrammatically, l'istesso) the same; applied to the manner of articulation, tempo, etc."
So the term usage may have been popularized in music by someone who didn't translate it well, or something... Or, like you said - maybe an archaic usage that stuck in music and nowhere else.