Okay kiddo, lex loci arbitri is a fancy way of saying "the law of the place where the arbitration is happening".
Imagine you and your friend got into an argument over a toy and you both decided that instead of going to mommy or daddy to sort it out, you would ask a wise and neutral neighbor to help you resolve the issue. That wise neighbor would be like the arbitrator or judge in your case.
Now, the lex loci arbitri would be the rules or laws that the wise neighbor would follow to make their decision. So, if you and your friend were in a different country, the wise neighbor would follow the laws of that country to decide who should get the toy.
It's important to follow the lex loci arbitri because it helps ensure that the decision made is fair and in accordance with the laws of the place where the arbitration is happening.