I feel ひるめし is a kind of rough language, it's like a word that blue-collar workers would use.
I think ひるごはん is the most popular word for lunch, you could use it in any situation.
昼ごはんはもう済みましたか。Have you had lunch already?
昼ごはんを食べに行きませんか。Do you want to go for lunch?
In addition, お昼ごはん is more polite than 昼ごはん and we could just say 昼 or お昼 for lunch in casual conversation.