1. (pronoun) he, she, him, her, it - like all pronouns and personals, takes a when following ki, i, kei and hei but does not take a when used as the subject of the sentence, except in some dialects. Never occurs after he, te and ngā and is not used after the prepositions a, o, mā, mō, nā, nō or with tā and tō.

(Te Kākano Textbook (Ed. 2): 13;)