18.04 is the last release that comes with LXDE, wikipedia even lists the requirements
System requirements for Lubuntu 18.04 LTS included a minimum of 1 GB of RAM, although 2 GB was recommended for better performance, plus a Pentium 4, Pentium M, or AMD K8 CPU or newer.[139] The RAM requirements increased from Lubuntu 17.10.
But bigger picture my point was: Lubuntu's focus has changed, so it's not for me any more.