Load time dynamic linking comes into play when the system starts a program that uses load time dynamic linking, using the information the linker placed in the file to locate the names of the DLL(Dynamic Link Library) that are needed by the process.
The run time dynamic linking comes into play after the application calls the load library functions and the system locates the DLL. Basically it allows a process to keep running even if a DLL is not available, this is done by the binding of objects, usually generated from one or more previous link-edits, to generate a runnable process.