Only when + PRESENT SIMPLE + will INVERTED SUBJECT – English Grammar Profiler
In the English Grammar Profile, C2 point 66 in the category of FUTURE is defined as:
INVERSION present simple with ‘only when’ (followed by ‘will’ and inverted subject) to refer to the future.
A search on Google News:
A search in Ted corpus for:
only when * will {pr}
only when you really care will they leave their fears behind
This is an incredibly rare structure.
An iWeb search for:
only when _P _V
1 ONLY WHEN IT IS 3008
Then a check for ‘will’ in COCA results shows that finding ‘will’ is less than 10% and inversion does not exist.
1 2019 SPOK Fox_Baier
The bill states that officers will be able to use lethal force only when it is necessary, and if there are no other options.
74 1999 ACAD MusicEduc
Children will need more assistance, of course, but the teacher should provide help only when it is needed and stay out of the way when it is not.
2 ONLY WHEN THEY ARE 2080 3 ONLY WHEN YOU ARE 1978 4 ONLY WHEN YOU HAVE 1544 5 ONLY WHEN YOU NEED 841 6 ONLY WHEN IT ‘S 813 7 ONLY WHEN YOU ‘RE 647 8 ONLY WHEN WE ARE 603 9 ONLY WHEN THEY HAVE 493 10 ONLY WHEN WE HAVE 483 11 ONLY WHEN I ‘M 460 12 ONLY WHEN I WAS 445 13 ONLY WHEN YOU WANT 351 14 ONLY WHEN YOU GET 343 15 ONLY WHEN I AM 333 16 ONLY WHEN IT COMES 329 17 ONLY WHEN HE IS 328 18 ONLY WHEN I HAVE 304 19 ONLY WHEN IT WAS 291 20 ONLY WHEN THEY ‘RE 282 21 ONLY WHEN IT HAS 230 22 ONLY WHEN YOU CAN 227 23 ONLY WHEN THEY WERE 226 24 ONLY WHEN HE WAS 223 25 ONLY WHEN YOU USE 221 26 ONLY WHEN YOU FEEL 211 27 ONLY WHEN YOU KNOW 204 28 ONLY WHEN YOU DO 202 29 ONLY WHEN THEY NEED 176 30 ONLY WHEN YOU START 161 31 ONLY WHEN I STARTED 160 32 ONLY WHEN HE HAS 156 33 ONLY WHEN I GOT 145 34 ONLY WHEN I NEED 144 35 ONLY WHEN SHE IS 131 36 ONLY WHEN YOU ‘VE 125 37 ONLY WHEN I HAD 121 38 ONLY WHEN YOU SEE 119 39 ONLY WHEN THEY CAN 118 40 ONLY WHEN I FEEL 104 41 ONLY WHEN THEY FEEL 102 42 ONLY WHEN SHE WAS 102 43 ONLY WHEN THEY GET 101 44 ONLY WHEN YOU LOOK 99 45 ONLY WHEN I WANT 97
46 ONLY WHEN IT CAN 89