[1] He signed with the National Football League's Dallas Cowboys on May 1, 2016, after going undrafted in 2016 NFL draft, but was part of the team's training camp cuts in August following an injury.

Arjen was selected 2010 Defensive MVP of the Windsor & Essex County Secondary Schools Athletic Association's all-city team.

Colquhoun accounted for 2,000 all-purpose yards and 16 touchdowns in 2010, rushed 14 times for 83 yards and contributed three pass break-ups in the Green Griffins' 48-23 victory over Brantford Assumption in the 2010 Ontario Federation of School Athletic Association's Western Bowl.

His 55-yard gallop set up his own 3-yard TD run vs. London Catholic Central in the OFSAA West Regional championship and scored on runs of 95 and 2 yards vs. Sarnia in the Southwestern Ontario Secondary School Athletic Association's title game.

[3] After a football camp in 2011 in Cleveland, OH, Arjen hit radars of NCAA recruits, earning the nickname "The Canadian Flash".

He was a part of a 13-1 Michigan State Football team that was 7–0 at home and ended the season on a 10-game win streak.

That year they won the 2013 B1G Ten Champion, as the team beat Ohio State University, 34–32.

[6] As a junior, he appeared in 11 games as a backup cornerback, collecting 12 tackles and 2 pass breakups.

The team had a successful record of 11–2 and finished their season as 2014 Cotton Bowl Classic Champion, defeating Baylor University 42-41.

[3] Colquhoun was signed as an undrafted free agent by the Dallas Cowboys after the 2016 NFL draft on April 30.