Ellison signed a new deal before the game and marked the occasion by firing a superb 35-yard volley past Josh Lillis to give the Shrimps the vital second goal in a tight game.
The goal seemed to shock Dale, who conceded a third three minutes later when Andy Fleming slotted home a Will Haining cross from 12 yards.
Morecambe took the lead in the ninth minute through central defender Chris McCready.
Ryan Williams swung in a right-wing corner and McCready evaded his marker to stab the ball past Josh Lillis from close range to give his side the perfect start.
From there Rochdale enjoyed the greater share of possession and had a golden chance to level the scores when Terry Gornell turned past McCready but saw his shot superbly saved by Barry Roche low down.
For all their neat football, Keith Hill's could not break the Morecambe defence down as they slumped to a second successive 3-0 defeat following Tuesday's home reverse at the hands of Accrington.
- Sports & Recreation
- Josh Lillis
- Andy Fleming