I only know that it exists also in arabic, but i found little sources about the hebrew version that didn't give me enough information. i don't even know it's name. help please?
It's a ligature found mostly in Sephardic texts. Its origin is mostly in Ladino and Judeo-Arabic, where the aleph+lamed combination is very common. But it pops up in Hebrew texts too. Arabic use a ligature here too, as you noted, which probably contributed to its development. I've only ever heard it called "aleph-lamed", but it may have another name.
Also try asking in /r/AcademicBiblical and /r/Judaism.