Thanks very much for the replies. The 3 kids were taken back to Donegal by relatives before 1911 and are in the census there.
They may never have been in a children's home as such.
Orphaned children would have been dealt with by the parochial board. An application for 'relief' would have been made to the board, which would have decided what to do with them. Their options were basically to send them to the poorhouse, or to pay someone to look after them in their home. This could be a relative, or someone completely unrelated. I think most parochial boards preferred to board children out with someone, but this was not always possible.
The board would always try to find someone else to take on the responsibility (and expense) of looking after paupers including orphans. It may be that the board contacted the relatives in Donegal and asked them to take the responsibility, and that the relatives preferred to take the children home with them rather than pay for their upkeep in West Lothian.
If - and it's a big if - the records of the Uphall Parochial Board have survived, that's where to look for the answer. If they have not, then I think the chances are that the children were taken to the poorhouse rather than to a specific children's home.
There wasn't a poorhouse in every parish. Often a group of parochial boards would pool resources and provide a combination poorhouse for a group of parishes.
I am sure that WLFHS will know about poorhouses in West Lothian and about surviving parochial board records.