"Fornoni"?
I've heard of hundreds of Italian marques but that's a new one!
AFIAK it doesn't show up on the (nearly comprehensive) big Map of Italian Cycle Brands AKA Italia Bicycle Map, but there's always gonna be a few that didn't get included, especially if "Fornoni" was in the South (or out of country), so tell us more about that brand.

EDIT: came across your other post
https://www.bikeforums.net/classic-v...noni-frme.html
asking for info on Fornoni and [MENTION=333224]juvela[/MENTION] posted many links to articles on the racer (and Olympic champ in 1960) Giacomo Fornoni.
There's no mention of him fronting a bicycle brand but it's a common tradition in Italy for a successful racer to cash in on his name applying it to a bicycle (contract-built by a multitude of makers). He did race for Molteni...FWIW but this frame in question doesn't ring any bells with attributes of (oh say) Colnago or DeRosa, IMO
He seems to have been from Bergamo, also FWIW