I remember this level. Its after possesing the slig on the top level, going left and shooting the other slig, then dropping down a level and shooting the slig to the right. You then tell Elum to wait before hoisting all the way up.
But you do make the jump to the left with Elum. I did it again just then. Leap when Elum is at the uttmost edge of the gap.
Keep trying!
It's the only way to finish the level!