Well, Adélaïde is today pr. a-day-la-EED in (Anglo-)French... so I would give an educated guess that Adelais (Adélaïs?) could've been pr. a-day-la-EES. Contract a-day-la-EES and you'll get a-LEES, which is the modern French. pr. of Alice according to BtN.
But I still could be way, way off though.
Proud adopter of 15 punctuation marks; see my profile for their names.