The subject of this article or section is part of Children's Week, a seasonal event that lasts one week. Once the event has run its course, this will no longer be available until next year, but there are no guarantees.
The quest giver and this quest are only available during Children's Week.
If you do not finish the questline and return the whistle, it will disappear from your inventory in about a week.
Patch changes
Hotfix (2009-04-30): "If a player loses their Orphan Whistle at any time during the in-game Children's Week event they can speak to a Matron in cities to receive a replacement. Players can now obtain another orphan whistle from an orphan matron, even if they have completed all the associated orphan's quests."