What do you need to trigger arcade gannons quest?

To trigger Arcade Gannon's quest in "Fallout: New Vegas," you must first have him as a companion. His quest, "For Old Times' Sake," becomes available after you complete the mission "The House Always Wins" or if you have the "Wild Card" questline active. Additionally, you should have progressed far enough in the game to reach the New Vegas Strip and have the option to speak with him about his past. Once these conditions are met, the quest will activate when you engage him in conversation about his history with the Brotherhood of Steel.