Elson opened the scoring at 7:22 of the first period, and Matt Bellerive made it 2-0 Red Deer at the 8:58 mark of the period.
Brock Montgomery got the Ice on the scoreboard at 14:52 of the first, and Sam Reinhart tied it in the second period with his 27th goal of the season.
Elson scored the winner at 19:33 of the second period, and Dieno sandwiched a pair of goals around Dominik Volek in the third to complete the scoring.
Patrik Bartosak made 23 saves for Red Deer (27-20-6), while Mackenzie Skapski finished with 24 stops for Kootenay (23-27-2).
The Rebels were 1 for 3 on the power play, while the Ice were 0 for 2.