It is used if it is followed by όνομα: What/which name should we give to our child?= τι/ποιο όνομα να δώσουμε στο παιδί μας;. What a name this is!= Τι όνομα είναι αυτό! Ποιο is better translated as which, not who. So ποιο είναι το όνομά σου;= which is your name? that makes more sense than who, i think. :)
Ποιο is not "who" (that would be ποιος) but "which".
For example, Ποιο όνομα έχει ο ελέφαντας; "Which name does the elephant have?"
I suppose you could consider ποιος a version of this, short for "which person" -- as that is also the masculine form (e.g. Ποιος ελέφαντας πήγε εκεί; "Which elephant went there?").
Is it ποια instead of ποιος because όνομα is neuter? It seems always to be ποια for this idiom for people or animals. I got confused at first because elephant is grammatically masc. Based on mizinamo's comment that is what I think is going on, but I want to check. Ευχαριστώ
The όνομα is not όνομά (no tone on the Ultima--the last syllable of the word). Does this mean that the του belongs to the elephant?
Το όνομα / του ελέφαντα
It's not "its name / elephant" but "the name / of the elephant".
That said: many sentences in this course do not have a second accent where they should, because of technical difficulties in the early phases of the project. So unfortunately you cannot rely on the presence or absence of a second accent at the moment. The second version, which is being worked on, will remedy this.