I think no-one understands that. To me it sounds like something someone made up when translating Lord Of The Rings. Like a plant growing only in Lothlórien. (But I can see how it may mean the same as "haltioissaan oleva" and was used 200 years ago.
Or like Lönnrot would use discussing mental states induced by Finns' magical medicines.
I mentioned haltiokas at work; they also said elves...