Did you scan the site?
Lubuntu 18.04 LTS was the last supported release of Lubuntu for i386 yes, but there was a later non-LTS release (so we released the more modern LXQt on i386 too 
).
The Lubuntu team documented i386 here, and I wrote a bit about i386 when Lubuntu 18.04 LTS reached EOL for flavors, such as here but elsewhere too.
FYI: As I’ve written many times, I’m still an i386 user, and what I’d use (& do use) I’ve also said. My IBM Thinkpad t43 still has 18.04 on it, the others still Debian…