tiling around an arch

I have been asked to tile a bathroom for a friend. There are two arches in the room (window and niche). My problem is; how do I do a neat job? considering the tiles will not go inside the arch itself but stop at the edge of the wall. Can you get bendy plastic trim, of the kind used for plastering?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.