The Guidelines may not give a direct example of conjunctions used in
composite titles. However, if one looks to the description of the
<title> element, one discovers some permissible nesting :
<titlePart>Tiny Spring Bulbs</titlePart>
In this case the "or" belongs to the title but to neither <titlePart>.
One could wrap the "or" in its own <titlePart>
Francois Lachance, Scholar-at-large
per Interactivity ad Virtuality via Textuality