I was doing some very-much-needed mundane sewing last night, but
thinking about more interesting stuff--like those elf collars. They
do not look like mandarin collars--they curve up from the shoulders
rather than making a right-angle turn, and I can't see any hint of a
seam line (though it could be covered with embroidery).

Ever couple of decades the vagaries of fashion bring around the
"funnel collar" in which the collar is simply an extension of the
blouse. I didn't have time to really work it out, but a quick swatch
showed that it would probably work.

Grab a pattern that has a high neckline (called a "jewel neck" for
women, or just a regular men's shirt pattern). there will be the
shoulder line, and then a curved dip down for the neckline. Starting
about a half-inch away from the neck curve (because you don't want
the high collar to be too tight draw the new neckline, about two
inches high.
It's going to look like the outline of a turtle-neck sweater. Draw a
curve from the collar to the shoulder rather than having a
right-angle turn.

Try it on (I slashed the front deeply enough to be able to put my
head through) and draw the curves on the upper collar where you want
them.

that's as far as I got last night, but I though I'd toss it out for
others to play with. The line looks right . You either have to have
it open at the front, slashed deep enough to go over the head, or
just slashed to the collar line and have it open up the back.
Obviously it will need to be faced, and if it's a soft material
probably underlined as well.

--Ann, who does not feel like being at work on Monday morning.

That's as far as I got last night, but