The distinction applies only to the 3rd person singular pronoun. Note also that the oblique form of the 3rd person singular pronoun is used as the subject in equational sentences, in coordinate NPs, and when followed by intensive srefi ‘self’.
Source: Nickel and Wilner 1984: 23
Source: Nickel and Wilner 1984: 31
Source: Nickel and Wilner 1984: 22
Source: Nickel and Wilner 1984: 38
Source: Nickel and Wilner 1984: 47