If I'm holding my wallet in my hand so my friend can see it, and if I want to tell him that I lsot it sometime in the past, I needn't bother telling him/her I found the wallet again because he can see it in my hand.

In such circumstances, can we use the past perfect to tell our friend that we lost it, since it happened some time in the past before we found it again? Or does the other action need to be mentioned to validate the use of the past perfect?

"I had lost my wallet the other day." (but as you can see I found it.)

Because the finding naturally succeeds the losing, past perfect is not called for anyway.
Students: Are you brave enough to let our tutors analyse your pronunciation?
Hi, What about when the order of events is unclear/less clear?
Let's have your example. English isn't about hypothesis.