Maybe Ridley Scott was visiting the Welles house for his planned sequel to RKO 281!
Anyway, thanks for providing the nice photos... From the pictures provided, I'd guess this is indeed the house where Welles shot THE DREAMERS in the garden. In The DREAMERS footage we of course see it only from the inside, as it's supposed to be a villa in Milan, but it looks very similar to the outside of this house, from the pictures you posted.
Here's some more of Orson addresses for you to visit, although I'm sure many are no longer of any significant interest, probably having been destroyed or replaced by much newer structures...
8545 Franklin Avenue - Orson lived at this address while shooting CITIZEN KANE.
427 North Canon Drive, Beverly Hills - Office of Mercury productions from 1944 to 1948 - probably now a shopping mall.
136 South Carmelina Drive, Brentwood - the 10 room house that Rita and Orson lived in after getting married.
1451 Cahuenga Blvd. (off of Sunset) - site of the Hollywood Canteen where Orson sawed Rita and then Marlene in half during WW II - now probably a condo.