Question: When I start emacs, I can use the --title= option to control the title of the x-window that holds the emacs application. Is it possible to change the title after emacs starts from elisp?

Answer: 
```
M-x set-frame-name NewName RET

```

and from elisp

```
(set-frame-name "NewName")

```
I use

```
(setq frame-title-format "%b - emacs")

```

to include the current buffer name in the frame title.