heya! I had a similar problem, to activate Julian's first event (his hypnosis performance) you have to also choose "offer your own services" when you choose "put your pets to work" (this is also how the rogue's storyline is unlocked!) once you get the event where you find one of his posters seeking assistants you have to choose to take the job yourself
after you've been hypnotized by him three times he'll send you a letter informing you that he has set up his circus in the forest, then you'll be able to visit it and continue his storyline
hope this helps!