Italian Fountain Sketch Monogrammed Tlb

Beautiful sketch taken on the motif of a dolphin fountain against a backdrop of mountains (the Alps?) in Italy. It is pasted on cardboard and monogrammed at the bottom left, but I have not been able to identify the painter. Only the fact that I bought it with a lot of works by René Gruau (1909-204) can be an additional clue. It is framed in a modern golden baguette and measures 14x28 cm without frame.I warmly thank a lover of Rome who pointed out to me that the fountain was the Fountain of the Sea Horses of the Villa Borghese. So it can't be the Alps in the background.