http://redump.org/discs/quicksearch/%E3 … %E3%82%8D/
Currently we have 6 discs "Lime-iro" vs. 7 discs "Raimuiro".
Wikipedia uses "Lime-iro": https://en.wikipedia.org/wiki/Lime-iro_Senkitan
VNDB uses a mix of "Lime Iro" and "Limeiro" https://vndb.org/v1314
The official website URL used "Limeiro": https://web.archive.org/web/20060105132 … meiro.com/
And there is a lime fruit in the logo so the English word "lime" is obviously intended.
I don't have a strong opinion on spacing as long as it's consistent but "Lime-iro" seems logical to me.
Additionally, we have 3 discs with a period after "Sakimorisu" and 4 without. All have a period (。) in the foreign title.