I am pretty sure she lost it at the ministers house
Explanation: Because when she was at the ball, she didn't come back with it.
Let me know if this helped! : )
D: the text gives no hint
The reader never really finds out where, exactly Madame Loisel loses the necklace. But, the author suggests that when she is getting ready to leave the ball, and it is very late, and she has had a great time, and does not want the feeling of joy and excitement that she has experienced by tarnished by the thought of her actual life at home, that it causes her to resists the efforts of her husband...