Prince Louis is a 4-year-old son of the Duke and Duchess of Cambridge and a fifth-in-line to the crown. However, to his 9-year-old brother Prince George and 7-year-old sister Princess Charlotte, he is something else. Apparently, to them he always has been and probably always will be Lou Lou.
The two oldest Cambridge children have long been referring to their little brother Lou Lou as a form of affection. In some ways, the nickname makes more sense than many of the other royal nicknames preferred by members of the royal family. For example, Prince George is called Tips by his parents because his royal initials are PG and there is a well-known British tea brand called PG Tips. That one is very appropriate for the future King of England.
Princess Charlotte is often referred to as Lottie by her parents, although Prince William has been heard calling her Mignonette, which is French for little cutie. Very appropriate for the correct princess we saw at the Platinum Jubilee, who showed good behavior and decorum.
Lou Lou is the perfect name for Prince Louis, as well as the energetic, funny, and fun little boy we all saw at Queen Elizabeth's Platinum Jubilee celebrations in early June. Now I want to go back and rewatch the video of Princess Charlotte scolding her little brother to see if she says something like Lou Lou thats enough! That would make a classic Mignonette/Lou Lou crossover.
The rest of the royal family is well-known for favoring a nickname. Perhaps it's what happens when people just bow or sink in a curtsy in front of you. Nicknames like Lilibet, Cabbage, and even my personal favorite, Gary (as William was a young boy) give Queen Elizabeth the opportunity to feel as a regular grandmother and mother.
I expect our little Lou Lou to never face a major issue.