Buddleja davidii, which is the most commonly grown one, has leaves which are opposite to each other on the branch. They have a sort of soft woolly feel to them, especially when young.
Unless I am very very wrong the leaves I am looking at are pinnate.
Down the centre of the stalk is a groove,a slight dent which is very typical of Sambucus nigra.
It may be to young a shrub to have the typical flat top white flower which are now on the bushes.
This link clearly shows what a single elder leaf looks like. One leaf consisting of 5 leaflets. Note the groove on the 1st pic
They can have more leaflets than 5.