I understand that Orleans and Microsoft.Hosting both work with .NET Standard 2.0 which is supported by .NET 4.8
See: Run Anywhere
For reference, I have already viewed this question which answers "Can Orleans be hosted in ASP.NET framework" but it does not answer HOW?: Is it possible to run Microsoft Orleans in classic ASP.NET MVC 4
Is there an example of hosting and consuming Orleans from .NET 4.8 using ASP.NET ?
You can if you split your front (ASP.net MVC) and MS Orleans cluster.
Your ASP.net MVC 4 run as client (With a client FROM Orleans 3+) for a .net7+ MS Orleans cluster.
The other advantage if you will be able to scale the cluster without scaling your "Facade" (front).
It's like your ASP.NET MVC 4 app act as reverse proxy or simple API front.