どき vs じ when using 〜時 as suffix


I'm trying to figure out exactly when to read 時 as 〜どき or 〜じ, when used as a
suffix, as in for example 空腹時, 食事時, as well as this sentence from a game I'm
playing:

> タウンメンバーの加入時に最大HP+20%

大辞林 defines とき（どき） as

>
> （８）（「どき」の形で）名詞や動詞の連用形の下に付いて，それにふさわしい，それの盛んな，あるいはそういう状態の時間であることを表す。（ア）時刻。時間帯。「昼飯―」「会社の引け―」「たそがれ―」（イ）時節。季節。「花見―」「木(コ)の芽―」「梅雨(ツユ)―」（ウ）時機。機会。「書き入れ―」「売り―」「引き上げ―」

and defines じ as

> ■二■ （接尾） （１）名詞に付いて，「とき」「おり」などの意を表す。「空腹―」「革命―」「第二次世界大戦―」

But it seems like じ just refers back to とき. Is there a specific one you should
use for each word, or can you use both 〜どき and 〜じ for a single word depending
on the context?




As a general rule, it is pronounced じ after an _on’yomi_ word and とき after a
_kun’yomi_ word. However, there are exceptions, and [食事時]{しょくじどき} is one of
them.

Curiously, 食事, despite being an _on’yomi_ word, also exceptionally tends to
take the politeness prefix お, rather than ご. I cannot explain why. I guess you
should memorize each exception.




As a general rule, it is pronounced じ after an _on’yomi_ word and とき after a
_kun’yomi_ word. However, there are exceptions, and [食事時]{しょくじどき} is one of
them.

Curiously, 食事, despite being an _on’yomi_ word, also exceptionally tends to
take the politeness prefix お, rather than ご. I cannot explain why. I guess you
should memorize each exception.

