Safari Zone after unlocking the usage of the blocks.
You can possibly get riolu in Pokemon black
Catch a Riolu and evolve Riolu.
in the wild
very very rare
If you have a lucario instead of trying to capture riolu why not breed lucario instead.
in safari zone
You can get him at the safari zone.
I think you mean Riolu. either by trading from another Generation IV game, or in the Meadow area of the Johto Safari Zone.
Yes, there are Sinnoh Pokémon HeartGold and SoulSilver. Kricketot, Buneary, Shinx, Luxio, Budew, Buizel, Floatzel, Chingling, Bronzor, Bronzong, Chatot, Carnivine, Pachirisu, Riolu, Skorupi, Hippopotas, Gible and Croagunk are all available in the wild in both HeartGold and SoulSilver.
Riolu is a Fighting type pokemon.
If your riolu is following you in heartgold or soulsilver you can talk to it.
You can get riolu by releasing 5 lucario's at the release point you will get a riolu ticket use it at the recruit point to get riolu.