Sorry if I'm resurrecting an old or incorrect thread, but this seemed like a good place to bring this up.
Another user in this thread mentioned that Ceni was missing, and I had the same experience after installing 2018.3.0 LXQt. I couldn't run Ceni from the Live CD, and I couldn't run it after I installed, either. Running the suggested update command from root didn't make Ceni work, either.
So, I do think Ceni may be unintentionally missing from the 2018.3.0 LXQt ISO. I don't have access to ethernet where I'm doing my install, only wifi, so Ceni would be a big help. My apologies if I'm not doing it right.
I'm a long-time sidux/aptosid user, and love siduction!
Thanks!