If you're talking about installing the Mageia 5 packages on Mageia 4, that's not a good idea - because of the dependencies on newer libraries, probably half of your system would need to be upgraded to Cauldron packages. Also, current LXQt requires slightly newer Qt packages, which are not available for Mageia 4.
So in short, it may be possible but it involve quite some work and fiddling.
For LXQt 0.7 there's a post with a link to the repo with my 0.7 packages:
viewtopic.php?p=47900#p47900