grammatical number - Plural of Latin masculine nouns ending in -o; eg. "folio"

Most discussions I have read on the issue of Latin plurals in English only address words ending in -us, -um, -x and the feminine nouns ending in -a. I would like to know how to make the English plural of Latin masculine nouns ending in -o, such as "folio". I am tempted to say and write "folia" as the plural of "folio", and similarly "bifolia" as the plural of "bifolio" etc, although my Oxford Advanced Learner's only quotes "folios". I am sure I have read both versions of this plural in academic print before. What would you advise?