Can you give a source for that? What I can find is, that the southeastern branch of the lake is called Lecco, but nowhere is that term used for the whole lake. Granted Como is also actually the term for the southwestern branch, but that term has established itself to refer to the whole lake, so much that the Italian Wikipedia article uses 'Lago di Como' as its title. Lario is accepted anyway.
Please accept "Lake Lecco" for Lario (Lake Como) since it's the other name of the lake amd actually the more correct one