illeism - (n)
The practice of referring to oneself as "he" or "she", or by one's name
Pretty straight forward. From the Latin ille, he, + -ism.
Its first citation is from 1809–10:
"For one piece of egotism … there are fifty that steal out in the mask of tuisms and ille-isms."
(Coleridge Friend (1818) I. 36 )
If Elaine had known about Jimmy's tendency to illeism she would never have ended up going out with him.
Parents and toddlers
The Big Lebowski