ubuntu can’t detect Windows 10 disk

I installed Ubuntu 16.04 on another SSD of my laptop. I have Windows 10 on hd1 and Ubuntu on hd0.

I wanted to dual boot using grub and I’m following a tutorial in order to add a Windows entry to the grub boot menu, but after I boot into Ubuntu the disk containing Windows 10 doesn’t even appear.

output from lsblk:

NAME   FSTYPE   SIZE MOUNTPOINT LABEL sda           447.1G             ├─sda4 vfat     191M /boot/efi   ├─sda2 ntfs   382.1G             ├─sda5 ext4    40.4G /home       ├─sda3 swap    14.9G [SWAP]      └─sda1 ext4     9.5G / 

sda is the disk of Ubuntu, another disk doesn’t appear. What can I do to manually detect my Windows disk?