harry potter - Could a house elf be made into a Secret Keeper?

Here's what we know about House-elves:

I believe, if a house-elf could be made into a Secret Keeper, it would not be a good idea for the elf to be its master's Secret-Keeper, as its master could order the elf to divulge the secret and I don't think the house-elf could refuse.

The Fidelius Charm is complex:

‘An immensely complex spell,’ he said squeakily, ‘involving the magical concealment of a secret inside a single, living soul. The information is hidden inside the chosen person, or Secret-Keeper, and is henceforth impossible to find – unless, of course, the Secret-Keeper chooses to divulge it. As long as the Secret-Keeper refused to speak, You-Know-Who could search the village where Lily and James were staying for years and never find them, not even if he had his nose pressed against their sitting-room window!’

_{Prisoner of Azkaban - page 153 - Bloomsbury - chapter 10, The Marauder's Map}

A single, living soul suggests just a soul; it doesn't say the soul has to be human. Conversely, inside the chosen person suggests that being a Secret-Keeper is specifically a human ability.

House-elf magic is different than wizarding magic. For example, house-elves can Apparate within Hogwarts; human witches and wizards cannot. We don't know enough about house-elf magic to adequately assess a house-elf's ability to be a Secret-Keeper; however, their profound loyalty toward their master, whether voluntary or indentured, does demonstrate a characteristic that would be conducive to being a good and strong Secret-Keeper.

However, what I noted above shows why we don't have enough canon information to say yes or no to this question; there is no information in canon that, when put together in good faith or the spirit of canon, suggests a definitive answer.