At times it would be very helpful to have up and down arrows while using the Windows 10 tablet onscreen keyboard. Is this possible?
You can enable the “standard” keyboard layout for the touch keyboard. This layout provides a better emulation of the hardware keyboard, including four cursor keys, Esc, Tab, Del, Ctrl, Shift, Alt, the Windows key and F1-F12 keys (enabled with the Fn toggle).
To enable this layout:
From the Start screen, open Settings (hidden behind the “hamburger” icon in the tablet mode). Another way to start the Settings app is the “All Settings” action icon in the notification center.
In the Settings app, select Devices → Typing.
Turn on the “Add the standard keyboard layout as a touch keyboard option” switch.
After enabling the layout you can switch to it using the rightmost icon in the keyboard options menu: