Riolu evolve by happiness during the day.
answer riolu doesnt evolve by level it evolves by care and love
If you don't want to wait 70 days for a Riolu, trade the free Riolu you can get in Diamond and evolve it.
lucario is not in the wild but you can get a riolu from an egg on iron island so just evolve it from that.
in the safari zone
in the meadow