Elford-Alliyu scored after 22 minutes folowing a knockdown by striker Enoch Showumni, who would add a third later in the game.
Elford-Alliyu's first was struck from 12 yards out and gave home goalkeeper David Button little chance.
Button got his hand to Elford-Alliyu's second goal in the 63rd minute, but the ball spun off the on-loan Tottenham goalkeeper's hands and into the net.
Rovers forged further ahead as Argyle pressed forward for a goal. The ball broke to Showumni and he raced away to fire under Button in the 80th minute.
Argyle, heading for their fifth successive defeat, managed a late consolatiuon through tireless striker Joe Mason, who latched on to a knockdown to make it 3-1.
Source: PA
Source: PA