I am not sure about the exact one you are looking for but I found another on the Internet:
I'll lend you for a little time a child of mine, He said ...
For you to love the while he lives ... and mourn for when he's dead.
It may be six or seven years, or twenty-two and three,
But will you, till I call him back, take care of him for me?
He'll bring his charms to gladden you. And shall his stay be brief,
You'll have his lovely memories as solace for your grief.
I cannot promise he will stay, since all from Earth return.
But there are lessons, taught down there, I want this child to learn.
I've looked the wide world over in search for teachers true,
And from the throngs that crowd life's lanes, I have selected you.
Now ... will you give him all your love ... nor think the labor in vain?
Nor ... hate me when I come to call ... to take him back again?
I fancied that I heard you say ...
“Dear Lord, it will be done!
“For all the joy Your Child shall bring, the risk of grief we'll run.
“We'll shelter him with tenderness. We'll love him while we may,
“And for the happiness we've known ... forever grateful stay.
“But shall the angels call for him much sooner than we've planned,
“We'll brave the bitter grief that comes ... and try to understand.” *