Delete all words that not starts with a specific character

Hello everyone, sorry if I ask trivial questions. I’d like to delete from a string all words that not starts with a specific character. E.g. @

My string:

lorem ipsum @name1 sic it @name2 dolorem @name3

Desired output:

@name1 @name2 @name3

If possible without using regex expressions.

Many thanks.

Alessandro