Sherlock Holmes and Arsène Lupin's murder riddle. Please help me to solve it.

A Friend of Mine recently sent me this riddle, and I can't solve it, this gives me insomnia so please try to solve it to help me.
This one's really hard but Itrust you guys ! ^^


Here is a transcript of an actual conversation between Sherlock Holmes and
Arsène Lupin. Nothing has been changed.
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Sherlock Holmes: All right Mister Lupin. Where were you and what were you doing yesterday when Mr Tronel was killed?
Arsène Lupin: I don't remember... Why do you accuse me? I didn't do anything... Oh I remember now, I was picking up my children at school at about 5:30pm.
Sherlock Holmes: Your children? Give me the names.
Arsène Lupin: Lily, Elvis and Ilah.
Sherlock Holmes: What about their age?
Arsène Lupin: I can only tell you that the product of their age equal thirty-six.
Sherlock Holmes: I need more information Mister Lupin.
Arsène Lupin: Elvis is .... No... I won't give you their age. I can only tell you that the sum of their age is equal to the number from the address of the house in front of my flat.
Sherlock Holmes: I still can't find their age! Just tell me the numbers!
Arsène Lupin: Don't shout at me, please, I hate when people shout at me. All right, the eldest has got long brown hair....
Sherlock Holmes: Oh, okay I see ... But, now I know that you are not telling the truth. 
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First, let me remind you that the conversation has not been modified in any manner.
Your task is to defy Sherlock Holmes. First, how can we know that Arsène Lupin is lying? (three elements at least are needed). Then, find the age of the eldest child.