Lance Armstrong

Lance Armstrong is a bicyclist who has competed in and won the Tour de France 7 times.

Season 12
Lance helped Binky get a petition passed for bike lanes in Elwood City.

Season 13
He gave advice to the kids when Mrs. MacGrady was diagnosed with cancer, since he had battled against cancer himself.

Arthur

 * 1202a. "Room to Ride"
 * 1301. "The Great MacGrady"

Behind the scenes
In 2012, a doping scandal caused Armstrong to be stripped of his former victories. However, this is only in the real world. The fictional version of him has yet to be affected.

Per his blacklisted status, he does not appear on the list of celebrity guests at the page for the Arthur TV show at the Marc Brown Studios website.