plaster moulding repairs

I would like to repair a Victorian mirror with ornate plaster mouldings. It has suffered over the years and there are a few pieces to reattach. Does anyone have any suggestions for what glue to use? Given it's going to be pretty fiddly, it would be good to use something with a reasonable open time.
Thanks for any help,

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Site Timeline 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.