understanding emulsification

this is a fairly simple question but i can’t seem to find a straight forward/consistent answer. i was researching why cream curdles with the addition of acidity to understand why sauces break, and i was wondering - is the mixture of heavy cream and lemon juice (whisked together) considered an emulsification? i saw something say that all sauces are emulsifications, but that confuses me because there is no emulsifier that i know being used in this situation. i thought you needed something like egg yolks, mustard, etc. to make an official emulsion. thanks for helping me!! submitted by /u/Syvannah